1. 配置各接口所属VLAN
[LSW1]vlan 10
[LSW1-GigabitEthernet0/0/1]port link-type trunk
[LSW1-GigabitEthernet0/0/1]port trunk allow-pass vlan 10
[LSW2]vlan batch 10 20
[LSW2-GigabitEthernet0/0/1]port link-type trunk
[LSW2-GigabitEthernet0/0/1]port trunk allow-pass vlan 10
[LSW2-GigabitEthernet0/0/2]port link-type trunk
[LSW2-GigabitEthernet0/0/2]port trunk allow-pass vlan 20
[LSW3]vlan 20
[LSW3-GigabitEthernet0/0/1]port link-type trunk
[LSW3-GigabitEthernet0/0/1]port trunk allow-pass vlan 20
[LSW4]vlan batch 10
[LSW4-Ethernet0/0/1]port link-type trunk
[LSW4-Ethernet0/0/1]port trunk allow-pass vlan 10
[LSW4-Ethernet0/0/2]port link-type trunk
[LSW4-Ethernet0/0/2]port trunk allow-pass vlan 10
2. 配置各交换机VLANIF接口的IP地址
[LSW1-Vlanif10]ip add 10.1.1.1 24
[LSW2-Vlanif10]ip add 10.1.1.2 24
[LSW2-Vlanif20]ip add 10.2.1.2 24
[LSW3-Vlanif20]ip add 10.2.1.3 24
3. 配置IS-IS基本功能
[LSW1]isis 1
[LSW1-isis-1]is-level level-2
[LSW1-isis-1]network-entity 10.1111.1111.1111.00
[LSW1-Vlanif10]isis enable
[LSW2]isis 1
[LSW2-isis-1]is-level level-2
[LSW2-isis-1]network-entity 10.2222.2222.2222.00
[LSW2-Vlanif10]isis enable
[LSW2-Vlanif20]isis enable 1
[LSW3]isis 1
[LSW3-isis-1]is-level level-2
[LSW3-isis-1]network-entity 10.3333.3333.3333.00
[LSW3-Vlanif20]isis enable 1
4. 配置BFD
[LSW1]bfd
[LSW1]bfd 1to2 bind peer-ip 10.1.1.2 interface Vlanif 10
[LSW1-bfd-session-1to2]discriminator local 1
[LSW1-bfd-session-1to2]discriminator remote 2
[LSW1-bfd-session-1to2]commit
[LSW2]bfd
[LSW2]bfd 2to1 bind peer-ip 10.1.1.1 interface Vlanif 10
[LSW2-bfd-session-2to1]discriminator local 2
[LSW2-bfd-session-2to1]discriminator remote 1
[LSW2-bfd-session-2to1]commit
5. 使能IS-IS的快速感知特性
[LSW1-Vlanif10]isis bfd static
[LSW2-Vlanif10]isis bfd static
6. 检查配置
（1）打开LSW1调试信息开关，使信息输出到VTY通道
[LSW1]info-center source bfd channel 1 log level debugging state on
<LSW1>debugging isis circuit-information
<LSW1>terminal debugging
<LSW1>terminal logging
<LSW1>terminal monitor
（2）关闭LSW2的g0/0/1，模拟链路故障，LSW1显示以下日志信息和调试信息
[LSW2-GigabitEthernet0/0/1]shutdown
